Crystal Error: The keycode assembly, BusinessObjects.Licensing.KeycodeDecoder.dll, cannot be loaded.

Issue:
When running a Crystal Report the B1 Usability Package add-on crash. If you look at the Windows event viewer may find an entry with the text:

"The keycode assembly, BusinessObjects.Licensing.KeycodeDecoder.dll, cannot be loaded."

There a multiple known issues that may cause the crash.
Please check solution 1 before checking solutions 2 and 3.

Solution 1 - Wrong datasource
Please check what datasource type the report is using. The most common issue is that the SAP datasource connection is used in the report.
B1UP only supporters using the OLE DB provider and not the SAP connector as there is a bug in the SAP connector. The core issue with using the SAP connection is that the SAP SDK becomes unstable and begins to fail running even the most simple SQL sentences. If you use the SAP Business One Crystal Report datasource a crystal report will disconnect the DI-API connect for the add-on (the bug) and the addon will fail. 
Please see this video: https://www.youtube.com/watch?v=j7kpj2tR3d4&feature=youtu.be and check what connection type the Crystal layout is using.
You will need to check all your Crystal Reports as having one run with the SAP datasource is enough to break the add-on.

Solution 2 - Corrupt Crystal installation.
If you look at Google: https://www.google.dk/search?q=The+keycode+assembly%2C+BusinessObjects.Licensing.KeycodeDecoder.dll%2C+cannot+be+loaded.&oq=The+keycode+assembly%2C+BusinessObjects.Licensing.KeycodeDecoder.dll%2C+cannot+be+loaded.&aqs=chrome..69i57.287j0j7&sourceid=chrome&ie=UTF-8

It is unfortunately a quite common error. Please try to reinstall the Crystal Run-time as this is what seems to solve most cases where solution 1 does not work/apply. 

Solution 3 - Test if it is environment-specific

You will need to identify if this issue is database-specific or machine-specific. Please take a copy of the database, restore it in a test environment, and see if it also happens there.

- If you can recreate it we need a copy of the database + crystals (Please open a ticket with support)

If you cannot recreate it on a test environment you will need to open a ticket with SAP support. 
In the ticket please state that you have the error "The keycode assembly, BusinessObjects.Licensing.KeycodeDecoder.dll, cannot be loaded." and a reinstall of Crystal Report run time have not resolved it (what everyone on google states fix the issue). SAP support will then need to investigate the issue and tell us what is the problem is and how it can be avoided. 

The Boyum support team can assist with any technical questions you might be met with from them on how B1UP calls the Crystal Report runtime, ect. We however cannot solve the issue without the help of SAP as the issue is with the Crystal runtime.